-deuterium. Also called heavy hydrogen. The mass of an atom of deuterium is about twice that of normal hydrogen atom. Unlike the nucleus of an ordinary hydrogen atom which contains only a proton, the nucleus of deuterium contains a poton and a nuetron.

-fusion. The joining of the nuclei of two atons to form the nucleus of a heavier element with the release of vast amounts of energy. Fusion occurs most readily with hydrogen and other light elements.

-fission. Nuclear reaction in which a heavy atomic nucleus splits into two approximately equal parts at the same time emitting neutrons and releasing very large amounts of nuclear energy.

-heavy water. Deuterium Oxide (D20). Water in which the hydorgen is replaced by deuterium. Occurs naturally in sea water.

-isotopes. Atoms of the same element (ie. having the same atomic number) which differ in mass number.

-mass number. The total number of protons and neutrons in each atom of a particular isotope of an element.

-neutron. An elementary particle that makes up all atomic nuclei except normal hydrogen. Neutrons have no electric charge and a mass only slightly greater than that of the proton.

-nuclear fusion (cold). Experimental electrochemical techniques performed at room temperature to fuse some of the components of heavy water and produce large amounts of heat as a by-product.

-nuclear fusion (hot). Nuclear reaction between light atomic nuclei as a result of which a heavier nucleus is formed and a large quantity of nuclear energy is released. For fusion to be possible, the reacting nuclei must possess sufficient kinetic energy to overcome the electrostatic field surrounding them. Temperatures associated with fusion reactions are therfore extremely high (millions of degrees). Hot fusion is believed to be the source of energy of the stars and occurs on earth during the explosion of a hydrogen bomb and during controlled themonuclear reactions are therefore extremely high (millions of degrees). Hot fusion is believed to be the source of energy of the stars and occurs on earth during the explosion of a hydrogen bomb and during controlled thermonuclear reactions.

-nuclei. Central part of an atom, the fundamental particles of which are the proton and neutron, except for hydrogen, which is composed of one proton only; it carries a positive charge and constitutes almost all of the mass of the atom.

-proton. A stable elementary particle with electric charge equal to that of the electron, but of the opposite sign. The proton is a normal hydrogen atomic nucleus and makes up all other atomic nuclei.